xndman,
Think of your pool as a boat. When its empty, with water around it, it floats. To keep a pool from floating the hydrostatic valve opens and lets water in to equalize the pressure on the vessel. When your pool is plastered you will be advised not to drain the pool completely for any length of time. The gound water should never exceed the height of the water in the pool so you should not have a problem.
Cost to bring out a backhoe, haul and place rock most likely exceeded $2000. Other trades somtimes charge extra for the additional effort needed. The plaster crew will usually put in a little extra work depending on how fast the ground water enters the pool. Don't bother pumping the pool out at this point. Wait until plaster. Good luck.

My message to all pool owners: Never drain your pool on your own if you are not 100% sure of its structural integrity and of the soil and water conditions. Hire a professional and make sure they have insurance so that in a worst case YOU WILL NOT BE RESPONSIBLE.

Thanks for the replies. Should I be worried at all about the pool after it's filled with water? Would you expect the pool co. to try to divert the water (underground) away from the pool? Once it's filled, I'll never empty it. For inormational purposes, the water currently in the pool (all from ground water) is probably about 4 ft deep in the deep end.

Wow, you have a really high water table. But this will have no effect on the pool once its full. I would be more concerned with what could happen if that water ever went away such as a severe drought. If you ever sell, be nice and tell the new owner so they dont float the pool.

When I get water coming in anywhere around half the depth of the pool or if it has high pressure and is blowing out walls I install a well point. Soemtimes if the water is extremely bad we will dig trenches through the center of the pool install a well point and let it sit for a week or two. The most expensive water hole that I ever dug was around $8000. All the dirt was saturated and unusable. I trucked in about 5 pallets of portland and mixed with the dirt to drive the water out.We also set a 12 foot deep well point with gravel and a 12 inch sewer pipe with a sump pump. I let the yard sit for 3 weeks and when we came back to dig it the water found its way to the well points and the portland did it's job.

Wow, that's elaborate.

For the most part, as others said, once the pool is filled with water, the water outside will see the density of the pool as 'neutral' and they should be at equilibrium with each other. As said, it's dangerous to leave a pool empty (not to mention a falling hazard to pets etc too) so it should not be during extreme weather events, and for as little time as possible.